Diagnosis

Diagnosis at Mayo Clinic

You're at risk of familial adenomatous polyposis if you have a parent, child, brother or sister with the condition.

If you're at risk, it's important to be screened frequently, starting in childhood. Annual exams can detect the growth of polyps before they become cancerous. At Mayo Clinic, at-risk children who have the defective gene or whose genetic status isn't known are screened every year starting at age 10. At-risk children who don't have the defective gene are screened periodically starting at age 15.

Mayo Clinic specialists use these screening tests for FAP and its complications:

  • Sigmoidoscopy. A flexible tube is inserted into your rectum to inspect the rectum and sigmoid — the last two feet of the colon. At Mayo, sigmoidoscopy is used to screen at-risk children who haven't yet developed polyps.
  • Colonoscopy. A flexible tube is inserted into your rectum to inspect the entire colon. At Mayo, colonoscopy is used after polyps start growing and after age 18, and if attenuated FAP is suspected or already diagnosed.
  • Esophagogastroduodenoscopy (EGD) and side-viewing duodenoscopy. Two types of scopes are used to inspect your esophagus, stomach and upper part of the small intestine (duodenum and ampulla). The doctor may remove a small tissue sample (biopsy) for further study.
  • CT or MRI. Imaging of the abdomen and pelvis may be used, especially to evaluate desmoid tumors.

Genetic testing

A simple blood test can determine if you carry the abnormal gene that causes FAP. Genetic testing may also detect whether you're at risk of complications of FAP.

Mayo Clinic specialists may suggest genetic testing if:

  • You have family members with FAP
  • You have some, but not all, of the signs of FAP

Ruling out FAP spares at-risk children years of screening and emotional distress. For children who do carry the gene, appropriate screening and treatment greatly reduce the risk of cancer.

At Mayo Clinic, genetics counselors discuss the pros and cons of testing with you, including the psychological and medical implications and confidentiality issues. If you choose genetic testing, your counselor and your doctor discuss the results with you.

The Molecular Genetics Laboratory uses the latest techniques to detect specific mutations in the APC gene associated with FAP. If the initial genetic test is negative, Mayo scientists can sequence the MUTYH gene to determine if you have MUTYH-associated polyposis.

Additional tests

Mayo Clinic specialists may recommend thyroid exams and other testing to detect other medical problems that can occur if you have FAP.

Treatment

Treatment at Mayo Clinic

If you have a few small polyps, your Mayo Clinic doctor can remove them during your colonoscopy exam. Eventually, though, polyps may become too numerous to remove individually. To prevent cancer, Mayo specialists recommend surgery for familial adenomatous polyposis, usually by your late teens or early 20s. Surgery may not be required for attenuated FAP.

Surgery doesn't cure FAP. Polyps can continue to form in the remaining or reconstructed parts of your colon, stomach and small intestine. But with careful monitoring, these polyps usually can be found and removed during colonoscopy before becoming cancerous.

Minimally invasive colorectal surgery

At Mayo Clinic, most colorectal surgery is done using minimally invasive (laparoscopic) techniques. Laparoscopic surgery is performed through several small incisions that require just a stitch or two to close. Minimally invasive surgery usually shortens your hospital stay and allows you to recover more quickly.

Mayo Clinic specialists use these surgeries to treat familial adenomatous polyposis and its complications:

  • Ileal pouch-anal anastomosis (J-pouch) surgery. The colon and rectum are removed while preserving your anus, allowing you to have normal bowel movements. At Mayo Clinic, J-pouch surgery is the preferred treatment for FAP. J-pouch surgery can affect fertility. Mayo medical geneticists and reproductive gynecologists advise prospective parents about their options.
  • Total colectomy. The colon is removed while preserving your rectum and anus, allowing you to have normal bowel movements. Mayo specialists consider colectomy only if you don't have polyps in your rectum.
  • Continent ileostomy. Mayo specialists may recommend this surgery if your rectum or anus is damaged and J-pouch surgery isn't feasible. In this procedure, your small intestine is connected to the outside body through an opening (stoma) on your abdomen. Bowel movements that would normally have emptied through the rectum are collected in a waste bag that attaches at the stoma. Mayo Clinic has a team of wound and stoma care specialists who provide you with counseling before surgery and education and compassionate support afterward.

Follow-up treatment

At Mayo Clinic, you are screened regularly and treated for complications of familial adenomatous polyposis that can develop after colorectal surgery, including:

  • Duodenal polyps and periampullary polyps. Mayo specialists may recommend surgery in some cases to remove the entire duodenum because these types of polyps can progress to cancer.
  • Desmoid tumors. Mayo specialists use a combination of medications, including nonsteroidal anti-inflammatory drugs, anti-estrogen, chemotherapy and, in some cases, surgery.
  • Noncancerous bone tumors. Mayo surgeons can remove these tumors for pain relief or cosmetic reasons.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.

Familial adenomatous polyposis care at Mayo Clinic

Oct. 20, 2015
References
  1. Ahnen DJ, et al. Clinical manifestations and diagnosis of familial adenomatous polyposis. http://www.uptodate.com/home. Accessed May 11, 2015.
  2. Familial adenomatous polyposis. Cancer.Net. http://www.cancer.net/cancer-types/familial-adenomatous-polyposis. Accessed May 11, 2015.
  3. Leoz ML, et al. The genetic basis of familial adenomatous polyposis and its implications for clinical practice and risk management. The Application of Clinical Genetics. 2015;8:95.
  4. Familial adenomatous polyposis. Merck Manual Professional Version. http://www.merckmanuals.com/professional/gastrointestinal-disorders/tumors-of-the-gi-tract/familial-adenomatous-polyposis#. Accessed May 11, 2015.
  5. Ravi V, et al. Desmoid tumors: Epidemiology, risk factors, molecular pathogenesis, clinical presentation, diagnosis, and local therapy. http://www.uptodate.com/home. Accessed May 12, 2015.
  6. Bonis PAL, et al. Familial adenomatous polyposis: Screening and management of patients and families. http://www.uptodate.com/home. Accessed May 11, 2015.